Developmental Psychology

Report
Research Methods
Psychology 117
Research Questions
• Does playing violent videogames produce
aggression in children?
• What are the long-term effects of early
malnutrition?
• How do children of different ages react to
a divorce of their parents?
Origins of Assumptions and Beliefs?
• Word-of-Mouth Folklore
– Friends and relatives
– Portrayals of children/families on TV/books
– Religious teachings
– Talk shows
• Personal Experiences
• Expert Opinions
• Research Evidence
Research evidence is valuable
because results are:
• Observations of many children
• Unbiased observers
• Reliable, valid methods of measurement
• Careful control
Theories
• An orderly, integrated set of statements
that describes, explains, and predicts
behavior
• Vital tools
– Guide and give meaning
– Practical action
• Theories  hypotheses
– Predictions about behavior
• Research Question vs. Hypothesis
• Need plan (research design) for
conducting specific activities (research
method)
• Examine whether a relationship exists
between variables
• Independent Variable
• Dependent Variable
– Does eating candy produce hyperactivity?
– Does playing violent videogames produce
aggression in children?
– Does drinking wine lower your risk for heart
disease?
– Does exposure to smoke increase the risk of
SIDS?
• Statistical Significance
• Reliability – consistency
• Validity
– External/ecological validity
– Internal validity
Correlational Research
• The Correlational Design
– 2 or more variables meaningfully related
– Correlation coefficient (r)
•+1.00 to -1.00
•Sign indicates direction
– Positive (+)
– Negative (-)
•Figure 1.2 Plot of a hypothetical positive correlation between the amount of violence that children
see on television and the number of aggressive responses they display. Each dot represents a
specific child who views a particular level of televised violence (shown on the horizontal axis) and
commits a particular number of aggressive acts (shown on the vertical axis). Although the
correlation is less than perfect, we see that the more acts of violence a child watches on TV, the
more inclined he or she is to behave aggressively toward peers.
Correlational Research
• Correlational studies ≠ causation.
–Causal direction unknown
–Could be due to a third,
unmeasured (confounding) variable
Experimental Design
• Cause/effect
• Systematically manipulate a variable
• Random assignment
– Control group
– Experimental/treatment group(s)
• Hold conditions constant
– Eliminate threat of confounding variables
Field Experiment
• Natural setting
• Example in text: Belgian delinquents living
in minimum-security institution for
adolescent boys
•Figure 1.3 Mean physical aggression scores in the evening for highly aggressive (HA)
and less aggressive (LA) boys under baseline conditions and after watching violent or
neutral movies. ADAPTED FROM LEVENS ET AL., 1975.
Field Experiment
• May not be aware that they are
participating
• Study the effects of malnutrition or
sensory deprivation on infant motor
development.
• Volunteers?
Natural/Quasi-Experiment
• Naturally occurring events
• No manipulation of variables
• No random assignment
•Table 1.4 Strengths and Limitations of General Research Designs
Self-Report Methodologies
• Interviews/Questionnaires
– Unstructured to structured
– Difficult with children
• Clinical Method
– Can ask follow-up questions specific to
individual being interviewed (thus, less
structured)
Self-Report Methodologies
• Limitations
– Honesty/accuracy
– Interpretation of questions
– Use with children
• Strengths
– Efficient (large amounts of data, short amount
of time)
– Confidentiality improves accuracy
Observational Methodologies
• Naturalistic Observation
– Observations in common, everyday (i.e.,
natural) settings
– Strengths: easy, behavior is natural
• Thus _________ validity is high…
– Limitations: frequency of behavior; reactivity
Observational Methodologies
• Structured Observations
– Laboratory setting
– Set up a scenario
– Strengths: same environment, attempt to
elicit low frequency behaviors
– Limitations: external validity?
Case Study
• a detailed portrait of a single
individual; can also describe groups
– Strength – depth
– Limitations
•Difficult to compare
•Generalizability
•Observer bias
Ethnography
• Collect data by living within the cultural
community for an extended period
– Strengths: understanding cultural conflicts
and impacts on development
– Limitations: subjective, may not be
generalizable
Psychophysiological Methods
• Examine relationship between
physiological responses and behavior
– Heart Rate – compared to baseline, decrease
may indicate interest
– EEG – brain wave activity, showing arousal
states; stimulus detection
• Strengths
– Can examine behaviors in infants/young
children before they can self-report
Psychophysiological Methods
• Limitations?
– High degree of inference
– Change in physiology due to stimuli?
•Table 1.3 Strengths and Limitations of Seven Common Research Methods
Designs for Studying Development
• Longitudinal Design
– Same participants over time
• Can assess stability
• Can identify trends
• Can help understand individual differences
Designs for Studying Development
• Longitudinal Design (con’t)
– Limitations
• Costly and time-consuming
• Selective attrition
• Practice effects
• Cohort effects
Designs for Studying Development
• Cross-sectional Design
– Groups of people of differing ages (although
sometimes the same age…) studied at one
point in time
– Strengths?
• Efficient (time & money), no practice effects or
attrition
– Limitations?
• Information on individual change is not available
• Confound age and cohort effects
•Figure 1.5 Example of a sequential design. Two samples of children, one born in 1998, and one born in 2000 are
observed longitudinally between the ages of 6 and 12. The design permits the investigator to assess cohort
effects by comparing children of the same age who were born in different years. In the absence of cohort effects,
the longitudinal and cross-sectional comparisons in this design also permit the researcher to make strong
statements about the strength and the direction of any developmental changes.
Designs for Studying Development
• Microgenetic Design
– Illuminate processes that promote
developmental change
• Repeatedly expose children ready for a
developmental change to experiences thought to
produce that change
• Monitor behavior as it changes
Designs for Studying Development
• Microgenetic Design (con’t)
– Strengths
• Able to see the process of change
– Limitations
• Time consuming
• Repeated observations
Table 1.5 Strengths and Limitations of Four Developmental Designs
• A researcher is interested in whether there is a
relationship between the sporting events in
which siblings choose to engage. This
researcher sent a survey to 500 different families
and asked parents to write down the age of
each child and to list in which sports each child
participated. The researcher collected all of the
surveys and examined whether there was a
relationship between siblings’ choice of sports.
– Correlational or Experimental?
– Method?
• Observation, interview/questionnaire, clinical method, case
study, ethnography, psychophysiological
– Cross-sectional, longitudinal, or sequential?
– IV and DV?
• A researcher is interested in whether drinking water right
before bed increases the likelihood that children will wet
the bed at night. The researcher recruits 50 5-year-old
children to participate in her study. Twenty-five children
are given two glasses of water two hours before their
bedtime (one glass per hour) and twenty-five children
are prohibited from receiving liquids within two hours of
their bedtime. The researcher collects information from
the parents of the children participating for one week –
parents are telephoned and asked to report whether the
child wet the bed each night.
– Correlational or Experimental?
– Method?
• Observation, interview/questionnaire, clinical method, case
study, ethnography, psychophysiological
– Cross-sectional, longitudinal, or sequential?
– IV and DV?
• A researcher was interested in how children
learn how to settle disagreements with peers.
The researcher talked to his 5-year-old daughter
and asked her to describe how she interacted
with her peers. The researcher then read a few
stories to his daughter about children her age
who got into disagreements and asked her what
she would do in that situation. The researcher
continued to interview his daughter like this for
five years.
– Correlational or Experimental?
– Method?
• Observation, interview/questionnaire, clinical method, case
study, ethnography, psychophysiological
– Cross-sectional, longitudinal, or sequential?
– IV and DV?
• A researcher was interested in whether the construct of
helplessness (e.g., low persistence, negative affect,
negative self-evaluations) is similar in toddlers,
preschoolers, and older children. The researcher
recruited a group of 2-year-olds and a group of 4-yearolds and brought them into a playroom setting. The
children were videotaped playing with impossible puzzles
and “helpless” behaviors were measured. The children
were brought back two years later (the first group of
children was then 4 and the second group was 6) and
were given another set of impossible puzzles. Helpless
behaviors were again measured.
– Correlational or Experimental?
– Method?
• Observation, interview/questionnaire, clinical method, case
study, ethnography, psychophysiological
– Cross-sectional, longitudinal, or sequential?
– IV and DV?
• A researcher is interested in whether boys or
girls are more aggressive when playing with
peers. The researcher goes to a playground
every day for 5 weeks and watches children
playing with one another. The researcher
records every instance of aggression that he
witnesses.
– Correlational or Experimental?
– Method?
• Observation, interview/questionnaire, clinical
method, case study, ethnography,
psychophysiological
– Cross-sectional, longitudinal, or sequential?
– IV and DV?
• A researcher is interested in whether a mother’s diet
during pregnancy influences her baby’s cognitive ability.
The researcher finds a group of women who were
malnourished during pregnancy and tests their infants’
cognitive skills and finds another group of women who
were not malnourished during pregnancy and gives the
same test to their infants. The researcher then gives all
of the children an IQ test when they reach the age of 6.
– Correlational or Experimental?
– Method?
• Observation, interview/questionnaire, clinical
method, case study, ethnography,
psychophysiological
– Cross-sectional, longitudinal, or sequential?
– IV and DV?
Ethical Considerations
• Research Ethics – standards of conduct to
protect participants from harm
– Protection from harm
– Benefits to risks ratio
– Informed consent
– Confidentiality
– Deception/Debriefing/Knowledge of Results

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